Thursday, September 6, 2012

Bitlocker

What is Bitlocker?

Bitlocker Drive Encryption allows you to encrypt all data stored on the Windows operating system volume and configured data volumes, and by using a Trusted Platform Module (TPM), it can also help ensure the integrity of early startup components. Bitlocker was updated with the release of Windows 7 and Windows Server 2008 R2.

Backing Up Bitlocker and TPM Recovery Information to AD DS

Backing up recovery passwords for a Bitlocker-protected drive allows administrators to recover the drive if it is locked. This ensures that encrypted data belonging to the enterprise can always be accessed by authorized users.

You can configure Bitlocker Drive Encryption to back up recovery information for Bitlocker-protected drives and the Trusted Platform Module (TPM) to Active Directory Domain Services (AD DS). Recovery information includes the recovery password for each Bitlocker-protected drive, the TPM owner password, and the information required to identify which computers and drives the recovery information applies to.

How it was implemented?

See http://technet.microsoft.com/en-us/library/dd875529%28WS.10%29.aspx for full instructions.

-Extended the Active Directory schema

-Updated the ACE to allow TPM recovery information to be backed up.

- Configure Group Policy to enable backup of Bitlocker and TPM recovery information in AD DS

Open Active directory on a Server 2008 R2 server or via RAST tools for Windows 7. Make sure Bitlocker is a select feature http://www.microsoft.com/download/en/details.aspx?id=7887

Right click the domain and click "Find Bitlocker Recovery Password".

You will need to enter the first 8 characters prompted for and it will search AD for the corresponding record.

If you know the computer host name you can search for the computer as normal; open the properties and you will see a Bitlocker Recovery Tab. This will provide the same details in order to gain access to the encrypted drive.

How to populate AD with the Recovery password manually?

This may be necessary should a machine fail to join the domain but the HDD Bitlocker has run.

What causes Bitlocker to start into recovery mode when attempting to start the operating system drive?

The following list provides examples of specific events that will cause Bitlocker to enter recovery mode when attempting to start the operating system drive:

Changing the BIOS boot order to boot another drive in advance of the hard drive.Having the CD or DVD drive before the hard drive in the BIOS boot order and then inserting or removing a CD or DVD.Failing to boot from a network drive before booting from the hard drive.Docking or undocking a portable computer. In some instances (depending on the computer manufacturer and the BIOS), the docking condition of the portable computer is part of the system measurement and must be consistent to validate the system status and unlock Bitlocker. This means that if a portable computer is connected to its docking station when Bitlocker is turned on, then it might also need to be connected to the docking station when it is unlocked. Conversely, if a portable computer is not connected to its docking station when Bitlocker is turned on, then it might need to be disconnected from the docking station when it is unlocked.Changes to the NTFS partition table on the disk including creating, deleting, or resizing a primary partition.Entering the personal identification number (PIN) incorrectly too many times so that the anti-hammering logic of the TPM is activated. Anti-hammering logic is software or hardware methods that increase the difficulty and cost of a brute force attack on a PIN by not accepting PIN entries until after a certain amount of time has passed.Turning off the BIOS support for reading the USB device in the pre-boot environment if you are using USB-based keys instead of a TPM.Turning off, disabling, deactivating, or clearing the TPM.Upgrading critical early start-up components, such as a BIOS upgrade, causing the BIOS measurements to change.Forgetting the PIN when PIN authentication has been enabled.Updating option ROM firmware.Upgrading TPM firmware.Adding or removing hardware. For example, inserting a new card in the computer, including some PCMIA wireless cards.Removing, inserting, or completely depleting the charge on a smart battery on a portable computer.Changes to the master boot record on the disk.Changes to the boot manager on the disk.Hiding the TPM from the operating system. Some BIOS settings can be used to prevent the enumeration of the TPM to the operating system. When implemented, this option can make the TPM hidden from the operating system. When the TPM is hidden, BIOS secure start-up is disabled, and the TPM does not respond to commands from any software.Using a different keyboard that does not correctly enter the PIN or whose keyboard map does not match the keyboard map assumed by the pre-boot environment. This can prevent the entry of enhanced PINs.Modifying the Platform Configuration Registers (PCRs) used by the TPM validation profile. For example, including PCR[1] would result in most changes to BIOS settings, causing Bitlocker to enter recovery mode.Moving the Bitlocker-protected drive into a new computer.Upgrading the motherboard to a new one with a new TPM.Losing the USB flash drive containing the start-up key when start-up key authentication has been enabled.Failing the TPM self test.Having a BIOS or an option ROM component that is not compliant with the relevant Trusted Computing Group standards for a client computer. For example, a non-compliant implementation may record volatile data (such as time) in the TPM measurements, causing different measurements on each start-up and causing Bitlocker to start in recovery mode.Changing the usage authorization for the storage root key of the TPM to a non-zero value.Disabling the code integrity check or enabling test signing on Windows Boot Manager (Bootmgr).Pressing the F8 or F10 key during the boot process.Adding or removing add-in cards (such as video or network cards), or upgrading firmware on add-in cards.Using a BIOS hot key during the boot process to change the boot order to something other than the hard drive.